Electrical – Thermal resistance unit

heatsinkthermal

Referring to the Infineon ICE2A365 datasheet.

In the datasheet, the thermal resistance from junction to ambient is 90 K/W.

What is K? Is it kelvin or degrees C.

If it is kelvin than changing it to degrees centigrade will be approx -183C/W, which does not make any sense.

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Best Answer

The only difference between them is the zero value (position of origin). Notice that the difference between any two points is the same on both the scales. So 1°C rise in temperature means 1K rise in temperature.

1 degree C is equivalent to 1 degree K.

See image:

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The SI units of thermal resistance are kelvins per watt or the equivalent degrees Celsius per watt (the two are the same since the intervals are equal: Δ1 K = Δ1 °C).